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-rw-r--r--drivers/alsamidi/midi_driver_alsamidi.cpp184
-rw-r--r--drivers/alsamidi/midi_driver_alsamidi.h38
2 files changed, 154 insertions, 68 deletions
diff --git a/drivers/alsamidi/midi_driver_alsamidi.cpp b/drivers/alsamidi/midi_driver_alsamidi.cpp
index d2a0076023..011758e5f7 100644
--- a/drivers/alsamidi/midi_driver_alsamidi.cpp
+++ b/drivers/alsamidi/midi_driver_alsamidi.cpp
@@ -37,85 +37,135 @@
#include <errno.h>
-static int get_message_size(uint8_t message) {
- switch (message & 0xF0) {
- case 0x80: // note off
- case 0x90: // note on
- case 0xA0: // aftertouch
- case 0xB0: // continuous controller
- case 0xE0: // pitch bend
- case 0xF2: // song position pointer
- return 3;
-
- case 0xC0: // patch change
- case 0xD0: // channel pressure
- case 0xF1: // time code quarter frame
- case 0xF3: // song select
+MIDIDriverALSAMidi::MessageCategory MIDIDriverALSAMidi::msg_category(uint8_t msg_part) {
+ if (msg_part >= 0xf8) {
+ return MessageCategory::RealTime;
+ } else if (msg_part >= 0xf0) {
+ // System Exclusive begin/end are specified as System Common Category messages,
+ // but we separate them here and give them their own categories as their
+ // behaviour is significantly different.
+ if (msg_part == 0xf0) {
+ return MessageCategory::SysExBegin;
+ } else if (msg_part == 0xf7) {
+ return MessageCategory::SysExEnd;
+ }
+ return MessageCategory::SystemCommon;
+ } else if (msg_part >= 0x80) {
+ return MessageCategory::Voice;
+ }
+ return MessageCategory::Data;
+}
+
+size_t MIDIDriverALSAMidi::msg_expected_data(uint8_t status_byte) {
+ if (msg_category(status_byte) == MessageCategory::Voice) {
+ // Voice messages have a channel number in the status byte, mask it out.
+ status_byte &= 0xf0;
+ }
+
+ switch (status_byte) {
+ case 0x80: // Note Off
+ case 0x90: // Note On
+ case 0xA0: // Polyphonic Key Pressure (Aftertouch)
+ case 0xB0: // Control Change (CC)
+ case 0xE0: // Pitch Bend Change
+ case 0xF2: // Song Position Pointer
return 2;
- case 0xF0: // SysEx start
- case 0xF4: // reserved
- case 0xF5: // reserved
- case 0xF6: // tune request
- case 0xF7: // SysEx end
- case 0xF8: // timing clock
- case 0xF9: // reserved
- case 0xFA: // start
- case 0xFB: // continue
- case 0xFC: // stop
- case 0xFD: // reserved
- case 0xFE: // active sensing
- case 0xFF: // reset
+ case 0xC0: // Program Change
+ case 0xD0: // Channel Pressure (Aftertouch)
+ case 0xF1: // MIDI Time Code Quarter Frame
+ case 0xF3: // Song Select
return 1;
}
- return 256;
+ return 0;
+}
+
+void MIDIDriverALSAMidi::InputConnection::parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver,
+ uint64_t timestamp) {
+ switch (msg_category(byte)) {
+ case MessageCategory::RealTime:
+ // Real-Time messages are single byte messages that can
+ // occur at any point.
+ // We pass them straight through.
+ driver.receive_input_packet(timestamp, &byte, 1);
+ break;
+
+ case MessageCategory::Data:
+ // We don't currently forward System Exclusive messages so skip their data.
+ // Collect any expected data for other message types.
+ if (!skipping_sys_ex && expected_data > received_data) {
+ buffer[received_data + 1] = byte;
+ received_data++;
+
+ // Forward a complete message and reset relevant state.
+ if (received_data == expected_data) {
+ driver.receive_input_packet(timestamp, buffer, received_data + 1);
+ received_data = 0;
+
+ if (msg_category(buffer[0]) != MessageCategory::Voice) {
+ // Voice Category messages can be sent with "running status".
+ // This means they don't resend the status byte until it changes.
+ // For other categories, we reset expected data, to require a new status byte.
+ expected_data = 0;
+ }
+ }
+ }
+ break;
+
+ case MessageCategory::SysExBegin:
+ buffer[0] = byte;
+ skipping_sys_ex = true;
+ break;
+
+ case MessageCategory::SysExEnd:
+ expected_data = 0;
+ skipping_sys_ex = false;
+ break;
+
+ case MessageCategory::Voice:
+ case MessageCategory::SystemCommon:
+ buffer[0] = byte;
+ received_data = 0;
+ expected_data = msg_expected_data(byte);
+ skipping_sys_ex = false;
+ if (expected_data == 0) {
+ driver.receive_input_packet(timestamp, &byte, 1);
+ }
+ break;
+ }
+}
+
+int MIDIDriverALSAMidi::InputConnection::read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp) {
+ int ret;
+ do {
+ uint8_t byte = 0;
+ ret = snd_rawmidi_read(rawmidi_ptr, &byte, 1);
+
+ if (ret < 0) {
+ if (ret != -EAGAIN) {
+ ERR_PRINT("snd_rawmidi_read error: " + String(snd_strerror(ret)));
+ }
+ } else {
+ parse_byte(byte, driver, timestamp);
+ }
+ } while (ret > 0);
+
+ return ret;
}
void MIDIDriverALSAMidi::thread_func(void *p_udata) {
MIDIDriverALSAMidi *md = static_cast<MIDIDriverALSAMidi *>(p_udata);
uint64_t timestamp = 0;
- uint8_t buffer[256];
- int expected_size = 255;
- int bytes = 0;
while (!md->exit_thread.is_set()) {
- int ret;
-
md->lock();
- for (int i = 0; i < md->connected_inputs.size(); i++) {
- snd_rawmidi_t *midi_in = md->connected_inputs[i];
- do {
- uint8_t byte = 0;
- ret = snd_rawmidi_read(midi_in, &byte, 1);
- if (ret < 0) {
- if (ret != -EAGAIN) {
- ERR_PRINT("snd_rawmidi_read error: " + String(snd_strerror(ret)));
- }
- } else {
- if (byte & 0x80) {
- // Flush previous packet if there is any
- if (bytes) {
- md->receive_input_packet(timestamp, buffer, bytes);
- bytes = 0;
- }
- expected_size = get_message_size(byte);
- // After a SysEx start, all bytes are data until a SysEx end, so
- // we're going to end the command at the SES, and let the common
- // driver ignore the following data bytes.
- }
+ InputConnection *connections = md->connected_inputs.ptrw();
+ size_t connection_count = md->connected_inputs.size();
- if (bytes < 256) {
- buffer[bytes++] = byte;
- // If we know the size of the current packet receive it if it reached the expected size
- if (bytes >= expected_size) {
- md->receive_input_packet(timestamp, buffer, bytes);
- bytes = 0;
- }
- }
- }
- } while (ret > 0);
+ for (size_t i = 0; i < connection_count; i++) {
+ connections[i].read_in(*md, timestamp);
}
md->unlock();
@@ -139,7 +189,7 @@ Error MIDIDriverALSAMidi::open() {
snd_rawmidi_t *midi_in;
int ret = snd_rawmidi_open(&midi_in, nullptr, name, SND_RAWMIDI_NONBLOCK);
if (ret >= 0) {
- connected_inputs.insert(i++, midi_in);
+ connected_inputs.insert(i++, InputConnection(midi_in));
}
}
@@ -160,7 +210,7 @@ void MIDIDriverALSAMidi::close() {
thread.wait_to_finish();
for (int i = 0; i < connected_inputs.size(); i++) {
- snd_rawmidi_t *midi_in = connected_inputs[i];
+ snd_rawmidi_t *midi_in = connected_inputs[i].rawmidi_ptr;
snd_rawmidi_close(midi_in);
}
connected_inputs.clear();
@@ -179,7 +229,7 @@ PackedStringArray MIDIDriverALSAMidi::get_connected_inputs() {
lock();
for (int i = 0; i < connected_inputs.size(); i++) {
- snd_rawmidi_t *midi_in = connected_inputs[i];
+ snd_rawmidi_t *midi_in = connected_inputs[i].rawmidi_ptr;
snd_rawmidi_info_t *info;
snd_rawmidi_info_malloc(&info);
diff --git a/drivers/alsamidi/midi_driver_alsamidi.h b/drivers/alsamidi/midi_driver_alsamidi.h
index ac3530b1b2..9265dede3d 100644
--- a/drivers/alsamidi/midi_driver_alsamidi.h
+++ b/drivers/alsamidi/midi_driver_alsamidi.h
@@ -46,12 +46,48 @@ class MIDIDriverALSAMidi : public MIDIDriver {
Thread thread;
Mutex mutex;
- Vector<snd_rawmidi_t *> connected_inputs;
+ class InputConnection {
+ public:
+ InputConnection() = default;
+ InputConnection(snd_rawmidi_t *midi_in) :
+ rawmidi_ptr{ midi_in } {}
+
+ // Read in and parse available data, forwarding any complete messages through the driver.
+ int read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp);
+
+ snd_rawmidi_t *rawmidi_ptr = nullptr;
+
+ private:
+ static const size_t MSG_BUFFER_SIZE = 3;
+ uint8_t buffer[MSG_BUFFER_SIZE] = { 0 };
+ size_t expected_data = 0;
+ size_t received_data = 0;
+ bool skipping_sys_ex = false;
+ void parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver, uint64_t timestamp);
+ };
+
+ Vector<InputConnection> connected_inputs;
SafeFlag exit_thread;
static void thread_func(void *p_udata);
+ enum class MessageCategory {
+ Data,
+ Voice,
+ SysExBegin,
+ SystemCommon, // excluding System Exclusive Begin/End
+ SysExEnd,
+ RealTime,
+ };
+
+ // If the passed byte is a status byte, return the associated message category,
+ // else return MessageCategory::Data.
+ static MessageCategory msg_category(uint8_t msg_part);
+
+ // Return the number of data bytes expected for the provided status byte.
+ static size_t msg_expected_data(uint8_t status_byte);
+
void lock() const;
void unlock() const;